1. Field of the Invention
The present invention relates in general to biopsy devices and, more particularly, to a biopsy device with a removable handle assembly.
2. Background Art
Biopsy devices have been known in the art for many years. In particular, many such biopsy devices have included a hollow outer cannula with some form of inner rod slidable within the outer cannula. The outer cannula conventionally consists of a proximal end, a distal end, and some form of a handle associated with the proximal end. The inner rod may typically take several different forms, including a sharpened stylet for insertion of the biopsy device into a patient, an inner cannula for sampling tissue, and/or an ejector rod for forcing the sample out of the outer cannula. The inner rod also typically includes a second or connection handle which may be secured to the handle portion of the outer cannula.
Such devices typically provide for the securable joining together of the outer cannula and inner rod handles when the inner rod is inserted within the outer cannula. Once the entire assembly is inserted within a patient, the inner rod is typically removed by separating the outer cannula and inner rod handles, and removing the inner rod by means of the inner rod handle. This type of structure is disclosed by Baldridge, U.S. Pat. No. 5,357,974, Tretinvak, U.S. Pat. No. 4,403,617, Tretinvak, U.S. Pat. No. 4,630,616, Lee, U.S. Pat. No. 4,655,266, and Strasser, et al., U.S. Pat. No. 4,838,282, among others.
Many of these types of devices require rotation of one of the handles themselves to unlock and separate the handles from one another, resulting in a change of orientation of the handles with respect to one another while the device is within the patient. This change in orientation of the handles, however, can often cause a corresponding change in the orientation of the inner rod with respect to the outer cannula, which can be undesirable to the user. Likewise, the manipulations of the overall device while in use can inadvertently separate the cannula handle from the rod handle, unlocking the device and causing the aligned tips of the cannula and rod to become misaligned. Other such devices contain a locknut securing device positioned directly atop the inner rod, which must be repeatedly rotated in order to remove the inner rod, thereby allowing the user to directly remove the rod itself from the interior of the cannula.
One application in which such devices are used is to repair crushed vertebrae. Typically, the cannula and rod portions of the biopsy device are inserted within the patient in order to locate the proper vertebra. After the cannula has been positioned within a vertebra, then an imaging device, such as an x-ray machine, is used to view the location of the cannula tip to determine whether it is positioned properly. If the cannula is not in the desired position, then the position of the biopsy device is adjusted as needed. Once it is determined that the cannula is positioned properly, then the inner rod is removed, and a form of cement or other binding element is injected into the vertebra through the cannula in order to reexpand the crushed vertebra. The devices in the prior art, however, present a particular disadvantage for this type of application. Once the user has removed the inner rod, along with its corresponding handle, the outer cannula handle remains in place, providing an undesired impediment to the imaging process.
It is therefore desired to provide a biopsy device with a separate handle assembly which is capable of being removed after the device is inserted into a patient, leaving the outer cannula and inner rod in place in the desired location, thereby eliminating the impediment to the imaging process presented by the presence of the outer cannula handle, as described above.
It is further desired to provide a biopsy device which allows the user to readily unlock and remove the handle assembly without affecting the orientation of the outer cannula and the inner rod with respect to one another, in order to prevent an undesired corresponding change in orientation of the distal ends of each.
Another object of the invention is to provide a biopsy device having a threaded region for the connection of external devices to the outer cannula, thereby allowing the outer cannula to be used with any number of medical devices requiring access to interior regions of the body.
It is also an object of the invention to provide a biopsy device in which the handle assembly may be resterilized after use and reused, resulting in significant cost savings over similar devices with attached handles which are disposed along with the rest of the device after use.
These and other objects of the present invention will become apparent in light of the present specification, claims, and drawings.
The present invention is directed to a biopsy device having a removable handle for alternatively attaching and removing a handle assembly while the cannula portion of the device is inserted into a patient, without affecting the orientation of the cannula portion of the device within the patient. The biopsy device comprises an outer cannula having a proximal end, a distal end, and a substantially hollow cross-section between the proximal and distal ends; an inner rod capable of being telescopically inserted into and retracted from the outer cannula and having a proximal end and a distal end; a sheath operably associated with and surrounding at least a portion of the outer cannula, and comprising a locking element; a handle assembly removably attachable to the sheath comprising a locking element and an opening for receiving at least a portion of the sheath; and a release member for releasing the handle assembly from attachment to the sheath by interacting with the locking elements associated with the sheath and the handle assembly. Further, the sheath may be at least partially inserted within the opening in the handle assembly and attached thereto, thereby retainably, yet releasably, locking the handle assembly to the outer cannula and the inner rod.
In another embodiment of the invention, the release member is a release element which is capable of toggling by the user between at least two positions in order to alternatively lock and release the handle assembly to the sheath.
In a further embodiment, the locking element associated with the sheath comprises at least one slot on the sheath which is capable of interacting with the release member to prevent separation of the sheath and the handle assembly.
In a still further embodiment, the locking element associated with the handle assembly comprises at least one aperture in the handle assembly which is capable of interacting with the release member to prevent separation of the sheath and the handle assembly.
In a yet further embodiment, the release member comprises a rotatable collar associated with at least one of the sheath and the handle assembly, and which is capable of being rotated at least partially about the sheath and the handle assembly when the two are joined together. The rotatable collar has at least two stationary positions, so that when the collar is in one position, a portion of the collar interacts with both of the locking elements associated with the sheath and the handle assembly to prevent separation of the sheath and the handle assembly. When the collar is in the other position, it avoids interaction with both of the locking elements, thereby permitting separation of the sheath and handle assembly from one another.
In an alternative embodiment, the release member comprises a slide member associated with at least one of the sheath and the handle assembly, and which is capable of lateral movement relative to the sheath and the handle assembly when the two are joined together. The slide member has at least two stationary positions, so that when the slide member is in one position, a portion of the slide member interacts with both of the locking elements associated with the sheath and the handle assembly to prevent separation of the sheath and the handle assembly. When the slide member is in the other position, it avoids interaction with both of the locking elements, thereby permitting separation of the sheath and handle assembly from one another.
In another embodiment of the invention, the opening in the handle assembly for receipt of the sheath is asymmetrical about at least one axis substantially perpendicular to the longitudinal axis of the opening.
In a further embodiment, at least a portion of the sheath has an asymmetrical cross-section substantially similar to that of the asymmetrical opening in the handle assembly, so as to be insertable into the handle assembly only when the sheath and the handle assembly are aligned in one particular orientation. This ensures that the outer cannula and the inner rod will be aligned in the same particular orientation relative to the handle assembly when the sheath and the handle assembly are locked together.
In still another embodiment of the invention, at least a portion of the outer surface of the sheath is threaded to enable the attachment of a comparably threaded component of a separate conduit for attachment to the outer cannula after the handle assembly is removed from the sheath.
An additional embodiment of the invention further includes an attachment member for securably attaching the inner rod within the outer cannula.
In a further embodiment, the attachment member comprises at least one prong associated with the inner rod for engaging with the sheath to securably attach the inner rod within the outer cannula.
Yet another embodiment includes a locking indicia for readily indicating whether the sheath and the handle assembly are in a locked or an unlocked orientation, relative to one another.
In alternative embodiments of the invention, the inner rod may comprise at least one of an inner cannula, a stylet, an obturator and an ejector rod.